The notion that
plants
can "talk" to one another was, until relatively recently,
dismissed as fantasy, but the reality of inter-plant communication
is now becoming an accepted part of mainstream science.

Although plants, by
definition, being "planted" in the ground, cannot move per se,
they are able to
send signals to one another, by means of volatile organic
compounds, and it is thought that not only can a plant communicate
with other plants, it may also engage in a "soliloquy"
by communicating between different parts of itself.

It is quite well
documented that if a plant is
attacked by an insect or fungal pest, it can signal to its
neighbors, so that they release compounds that repel the pests
directly, or attract other organisms that are antagonistic to them.

While the airborne
action of such messenger compounds is established, the idea that one
plant can warn another that it is in danger via a common (shared)
mycelial network (CMN) is rather more novel.

"Key roles in
facilitating nutrient transport and redistribution" are played
by the CMN, but they can also "facilitate defense against insect
herbivores and foliar necrotophic fungi by acting as conduits
for interplant signaling."

This is a beautiful
illustration of the interconnectedness of natural systems, and it
has been proposed that there are dominant "Mother Trees", which act
as hubs for the mutual connection of all the trees that grow in a
forest.

This connection is
thought to function to some degree through the mycorrhizal mycelium,
which lives in and around the tree roots, and serves as a conduit
for the transport of carbohydrates, nutrients and water between the
trees, via the
fungal
hyphae.

The mother trees
serve to "feed" the younger ones, and without them, most of the
seedlings would not survive.

Recent research has
shown that
without mother trees, attempts to regenerate forests often fail,
and when a mother tree is felled, the
survival rate of seedlings tends to be dramatically reduced.

In agriculture,
too, practices that leave the mycorrhizal (mycelial) network intact,
are thought to aid the absorption of water and nutrients from the
soil, and to improve the ability of plants to resist pathogens.

The influence of
one plant to influence (usually restrict) the growth of another is
termed
allelopathy, and functions via chemical messengers, e.g. the
production of
juglone by walnut trees, which was found to reduce the weight of
tomato seedlings
by about one third.

The whole system is
integrated, holistic and complex, and a new area of research has
emerged which aims to understand inter-plant communication
at the molecular level.

It appears that
plants may use a form of "language",
in which different molecules act as "words", although the precise
nature of the dialogue has yet to be deciphered.

Since RNA acts as a
translator of information from the DNA of an organism, it is
possible that the parasitic plant may be giving orders to its
"victim", to weaken its defenses, BUT the host might also be
delivering a masochistic response.

The question arises
of whether information can be similarly transmitted between other
organisms within the soil food web, i.e. earthworms, bacteria,
nematodes and other microbes, along with the plant roots, and their
associated mycorrhizal fungi.

To seek an
understanding of the complex communications and interactions that
take place between the soil food web organisms, at the molecular
level, may be a worthy aim, since the soil contains perhaps
one quarter of all the biodiversity on Earth.

Until this is
achieved, however, and in any case, it is clear that by supporting
this hidden biodiversity below the ground, the more visible
biodiversity above the ground is further buttressed.